Metal oil pan with an integrated oil filter

ABSTRACT

The invention relates to a metal oil pan for engines or transmissions, with an oil filter medium arranged therein, wherein part of the oil pan forms the bottom of an oil filter housing and a plastic half-shell forms a cover of the oil filter housing, and the oil filter medium is arranged between the oil pan and the plastic half-shell, the oil pan having metal rivets at its edge, and the plastic half-shell having bores at its edge, through which the plastic half-shell is fastened to the metal oil pan.

The invention is directed to a metal oil pan for engines ortransmissions with integrated oil filter which can be operated assuction or pressure oil filter.

Oil filters are employed in engines and transmissions to purify the oilused to lubricate the engine or transmission. Various types of oilfilters for engines or transmissions are known from the prior art. Ingeneral, they consist of a flat filter housing having two half-shells. Adisc-shaped or bag-shaped or a folded filter medium is fixed between thetwo half-shells. Metal screens, paper filters or polyester filter feltsare used as filter media. The filter half-shells joined together in anairtight fashion can be made of metal or plastic.

Conventionally, oil filtration in an engine or in an automatictransmission is effected using filters arranged separately outside theoil pan. To this end, the filter, oil pan seal and oil pan are used assingle components. The oil pan usually is made of metal. Thus,deep-drawn steel or aluminum-magnesium cast alloys are used in general.

The oil filters must be arranged so as to meet specific requirements.Thus, they have to be accessible as easily as possible and replaceableor removable in a simple fashion during maintenance works. In most ofthe cases, this is achieved by arranging the oil filters so as toprotrude from the engine level. In order to prevent the required spacefor the oil filter from becoming too large in size, the oil filter sizein motor oil filters is severely restricted. The oil filters thereforehave a small filter surface and as a result, they undergo foulingrelatively quickly and require frequent replacement. In the event ofautomatic transmissions, however, filter systems designed as servicelife filters are already available.

In general, the space available within the engine compartment in newconstructions of engines and transmissions is highly limited. Bulkyconstructions, particularly oil filter constructions protruding from theengine level are undesirable and disadvantageous.

To avoid these drawbacks, oil filters integrated in the oil pan ofengines or transmissions have been developed recently. Such integrationoffers the advantage of allowing rational utilization of the spaceavailable in the oil pan which otherwise merely is intended to receiveoil not being used in the engine or transmission circulation. Thus, theGerman patent 197 35 444.0 describes corresponding arrangements of oilfilter inserts in an oil pan. DE 197 35 445.9 describes the integrationof a suction oil filter in an oil pan made of plastic.

However, the integration of oil filters in oil pans involves a problemin that oil pans frequently are made of metal, while filter insertsgenerally consist of plastic material. For trouble-free function of theoil filter in the oil pan, it is indispensable that the joint betweenfilter insert and oil pan remains durably tight, enduring even overranges of high temperature. One should keep in mind that temperaturestress in the motor vehicle may range between −40 and +100° C.,depending on the user's geographic location and temperature of the oil.As a result of the dissimilar physical properties of metal and plasticmaterials, it is highly problematic to join these materials so as tocreate an oil pan with an oil filter insert that would ensure oilfiltration throughout the service life with perfect function andtightness.

The technical object of the invention was therefore to provide a metaloil pan for engines or transmissions, with an oil filter medium arrangedtherein, which oil pan avoids the above-mentioned drawbacks,specifically enabling long-term and trouble-free oil filtration, andalso has sufficient and permanent tightness even under major temperaturefluctuations.

The above technical object is accomplished by means of a metal oil panfor engines or transmissions, with an oil filter medium arrangedtherein, wherein part of the oil pan forms the bottom of an oil filterhousing and a plastic half-shell forms a cover of the oil filterhousing, and the oil filter medium is arranged between the oil pan andthe plastic half-shell, the oil pan having metal rivets at its edge, andthe plastic half-shell having bores at its edge, through which theplastic half-shell is fastened to the metal oil pan. Hereinafter, theoil filter medium is understood to be the unit comprised of the oilfilter insert with the oil filter material attached thereto.

In an alternative embodiment, the plastic half-shell has a metallicframe, through which the plastic half-shell is joined to the metal oilpan via electromechanical joining. In a preferred fashion, this iseffected by punctual welding together the metallic frame with the frameof the metal oil pan. In a particularly preferred fashion, the metallicframe consists of copper.

In a preferred embodiment, the oil filter medium is arranged in asupport frame which preferably consists of plastic. In a preferredfashion, the support frame is joined to the plastic half-shell. Usually,the support frame consisting of plastic is extruded around the filtermedium which subsequently is joined to the plastic half-shell likewiseconsisting of plastic.

In another preferred embodiment, support frame, plastic half-shell andoil pan are beaded together at their edges.

It is also preferred to use copper-clad weld-on tubular rivets as metalrivets. The weld-on tubular rivets are situated at the outer edge of theoil pan or arranged at the bottom of the oil pan. The plastic half-shellhas bores at its edge, so that the plastic half-shell can be placed on aparticular area of the oil pan, and the metal rivets on the oil pan arepassed through the bores. This is followed by welding the rivets, so asto make a firm joint between the oil pan and the plastic half-shell. Itis also preferred to insert seals between oil pan and plastichalf-shell, which seals preferably are attached to the support frame. Ina preferred fashion, profile gaskets, flat gaskets and toroidal sealingrings are used as seals.

The rivets arranged on the oil pan can be arranged in any number, shapeand position, depending on the shape of the plastic half-shell used andon the respective oil pan.

Furthermore, it is preferred to have flow ribs and/or support ribsmolded in the plastic half-shell and/or on the support frame, whichsupport the filter medium and the plastic half-shell on the oil pan.Moreover, spacer domes arranged on the plastic half-shell can be presentto support the plastic half-shell on the metal oil pan, said spacerdomes penetrating the filter medium or being firmly connected with same.

The oil pan according to the invention is produced via the followingsteps: Initially, plastic material is extruded around the filter mediumso as to form a support frame for the filter medium. The support framethen is joined with the is plastic half-shell. The support frame isprovided with a sealing medium. The plastic half-shell then is placed onthe particular area of the metal oil pan provided with the weld-ontubular rivets, so that the rivets at the edge of the correspondingparticular area of the metal oil pan pass through the bores arranged atthe edge of the plastic half-shell. The rivets then are welded on, sothat the plastic half-shell is firmly joined to the particular area ofthe oil pan.

The oil pan of the invention with integrated oil filter medium can beused for suction or pressure oil filtration.

Such integration of the oil filter housing in the oil filter pan isadvantageous in that separate arrangement of the oil filter housing inthe engine compartment is no longer required, thereby providing morespace for other engine components in the engine compartment.Furthermore, non-utilized space in the oil pan is made useful by suchintegration of the oil filter housing.

The above-described joint between plastic half-shell and metal oil panvia metal rivets or by means of a metallic frame which is welded permitsfirm and permanent joining of the metal oil pan and the plastichalf-shell. In this way, a compact assembly is formed, enablingfunctional and stable oil filtration throughout the service life of thevehicle, so that frequent replacement of the oil filter is not required.It is even possible to design the filter surface in such a way thatreplacement of the filter is no longer necessary during the averageservice life of the respective vehicle.

Another advantage of the invention is that the number of requiredcomponents is substantially minimized, resulting in a reduction of theoverall weight of the vehicle and in a substantial facilitation and costreduction of the production. According to the invention, a singlecomponent including the oil pan and oil filter medium is used, while inthe prior art not only the oil pan but also the oil filter must beinstalled in the vehicle as separate components.

The subject of the invention will be illustrated in more detail in thefigures below.

The FIGS. 1 to 4 and 7 show diverse cross-sectional views of variousembodiments of the oil pan according to the invention.

FIGS. 5 and 6 show top views of the oil pan according to the invention.

FIG. 1 shows a cross-sectional view. Numeral 1 denotes the oil pan madeof metal, numeral 2 denotes the plastic half-shell fastened to the oilpan by means of metal rivets. The oil filter medium is arranged betweenthe plastic half-shell and the bottom of the metal oil pan. By means ofsuch metal riveting, the filter material is beaded directly with the oilpan and the plastic half-shell at the edges thereof. In a preferredembodiment, a seal not shown in this illustration is provided betweenplastic half-shell and metal oil pan.

Numeral 8 denotes a support of the plastic half-shell at the bottom ofthe oil pan. The oil inlet in this embodiment is indicated by numeral 7and is situated at the right side of the oil filter beneath the oilfilter medium. The oil flows from the bottom upwardly through the filtermedium to the oil outlet. Furthermore, support ribs 10 are provided,ensuring stable positioning of the oil filter medium.

Numeral 9 denotes the beading between oil pan, plastic half-shell andfilter medium.

FIG. 2 describes a cross-sectional view of the oil pan according to theinvention, which differs from that in FIG. 1 in that the oil flows fromthe top to the bottom. The oil inlet is denoted with numeral 7 and issituated above the filter medium. The oil flows from the top downwardlythrough the filter medium and is collected at the bottom of the oil pan.The oil outlet nozzle is designed so as to reach the bottom of the oilpan and therefore, it is possible to return the oil from there via theoil outlet into the engine or transmission circulation.

The embodiments in FIGS. 1 and 2, which are characterized by thedifferent directions of oil flow through the filter medium, are usedaccording to the structure and shape of the oil pan employed, and alsofor space-related reasons. In this way, the oil filter insert and thedirection of oil flow can be adapted to the requirements of thepre-molded oil pan in any desired fashion.

To ensure sufficient tightness of the riveting, sealing elements oradhesives are preferably used at the edge. In a likewise preferredfashion, the metal rivets have a step arranged at the bottom and/or topend thereof.

FIG. 3 describes another embodiment of the oil pan according to theinvention. In this embodiment, the filter medium is held in a supportframe. The support frame usually consists of plastic, so that theplastic can be extruded around the filter medium. The support frame thenis joined to the plastic half-shell, so that direct joining of filtermedium and plastic half-shell as in FIGS. 1 and 2 is not necessary. Thisis advantageous in that a direct plastic-plastic joint is possible.Furthermore, the area of filter medium available for filtration isincreased by this measure and also, mass production of the respectivefilter medium is made possible.

In this embodiment as well, the oil inlet—according to numeral 7—isbeneath the filter medium, and the oil then is passed through the filtermedium and upwardly to the oil outlet. Again, numeral 10 denotes supportribs ensuring stable positioning of the filter medium.

FIG. 4 shows another embodiment of the oil pan according to theinvention. In FIG. 4, the support frame is not joined to the plastichalf-shell but beaded directly with the metal oil pan and plastichalf-shell via an elongation. This measure likewise ensures hightightness of the joint between oil pan and plastic half-shell.

FIG. 5 shows a top view on the oil pan according to the invention withthe oil filter insert which has bores according to numeral 5. Numeral 7denotes the oil inlet, and numeral 6 denotes the oil outlet.

FIG. 6 shows two top views with different arrangements of the oil filtermedium 3 in the oil pan 1. In this case, fixing plates 12 are molded onthe oil filter insert, which are capable of engaging with the weld-ontubular rivets 5 by placing and positioning, thereby firmly positioningthe filter in the oil pan with respect to all directions. The holdingplate 11 designed as a clip is capable of both radial and axialsecuring, thus ensuring a firm joint of the oil filter insert in the oilpan.

FIG. 7 shows a corresponding cross-sectional view of the embodiment inaccordance with FIG. 6. Numeral 6 denotes the oil outlet. Numeral 4denotes the metal rivets affixed to the bottom of oil pan 1. The oilfilter insert has the fixing plates 12 arranged thereon, which engagewith the weld-on tubular rivets 4, thereby creating a firm joint betweenoil filter insert and oil pan.

This arrangement achieves the following advantages. Oil pan and filterconstitute a firm unit, and the filter is held properly during assemblyand disassembly. It is not necessary to secure the filter to thetransmission housing. The filter can be disassembled, i.e., can bereplaced as well. Furthermore, no vibration noise is generated as aresult of the firm joint between filter insert and oil pan, unlike inthose variants where the filter rests loosely on the oil pan.

In general, supporting the plastic half-shell versus the metal pan iseffected by means of a single component welded firmly and tightly nearthe filter medium, by means of interconnected spacer domes, or by meansof a plastic frame having spacer domes and/or flow ribs molded thereon.Instead of the weld-on tubular rivets, a metallic frame deposited orembedded in the plastic half-shell can be used, protruding from theplastic half-shell at well-defined positions so as to enable punctualelectromechanical joining to the metal oil pan.

The oil can be conducted from the bottom through the filter by means ofan oil intake opening molded on the metal oil pan and appropriaterecesses on the plastic half-shell and/or the filter support frame,upwardly through the filter medium to the plastic half-shell, through anoutlet seal molded on the plastic half-shell to the suction side of theoil pump. Another possible oil flow would be that the oil is passed fromthe top through the plastic half-shell, through the filter medium abovethe metal oil pan, and then through a pipe or channel extending from thesuction side of the pump down to the lower filter compartment, throughwhich the oil can be sucked off.

1. An integrated oil pan filter unit, comprising: a transmission panbottom having an edge; a plastic half-shell top having a plastichalf-shell top edge and at least one bore in the plastic half-shelledge; and an oil filter medium having an oil filter medium edge,positioned between the transmission pan bottom and the plastichalf-shell top, wherein the plastic half-shell top and the oil filtermedium are joined directly to the transmission pan bottom by at leastone metal rivet passing through the plastic half-shell top edge and theoil filter medium edge, and wherein the at least one metal rivet passesthrough the at least one bore.
 2. The integrated oil pan filter unitaccording to claim 1, wherein the oil filter medium is arranged in asupport frame.
 3. The integrated oil pan filter unit according to claim2, wherein the support frame is joined to the plastic half-shell top. 4.The integrated oil pan filter unit according to claim 1, wherein the atleast one metal rivet is a copper-clad weld-on tubular rivet.
 5. Theintegrated oil pan filter unit according to claim 2, wherein the supportframe comprises plastic and has an edge, and wherein the plastichalf-shell top, transmission pan bottom, and support frame are beadedtogether at their edges.
 6. The integrated oil filter unit according toclaim 1, wherein the plastic half-shell top comprises a metallic frame.7. The integrated oil filter unit according to claim 6, wherein themetallic frame comprises copper.
 8. The integrated oil filter unitaccording to claim 2, further comprising a seal between the transmissionpan bottom and the plastic half-shell top, wherein the seal is chosenfrom profile gaskets, flat gaskets, and toroidal sealing rings.
 9. Theintegrated oil filter unit according to claim 1, further comprisingsupports for supporting the plastic half-shell top on the transmissionpan bottom, wherein the supports are chosen from flow ribs, supportribs, and spacer domes.
 10. The integrated oil filter unit according toclaim 9, wherein the supports are chosen from flow ribs and spacerframes, and the supports are molded in the plastic half-shell top. 11.The integrated oil filter unit according to claim 2, further comprisingsupports chosen from flow ribs and support ribs, wherein the supportsare molded in the support frame.
 12. The integrated oil filter unitaccording to claim 9, wherein the spacer domes penetrate the oil filtermedium.
 13. The integrated oil filter unit according to claim 9, whereinthe spacer domes are joined to the filter medium.
 14. The integrated oilpan filter unit according to claim 1, further comprising fixing platesmolded in the oil filter medium.
 15. An integrated pan filter unit foran automotive fluid filtration system, comprising: an automotive fluidpan bottom having at least one metal rivet, wherein the automotive fluidpan is a transmission housing; a plastic half-shell top having a plastichalf-shell top edge, at least one bore in the plastic half-shell edge;and an automotive fluid filter medium having an automotive fluid filtermedium edge positioned between the automotive fluid pan bottom and theplastic half shell top, wherein the plastic half shell top is joineddirectly to the automotive fluid pan bottom by the at least one metalrivet, at the plastic half shell top edge and the automotive fluidfilter medium edge, and wherein the at least one metal rivet passesthrough the at least one bore.
 16. The automotive fluid filtrationsystem of claim 15, wherein the at least one bore is positioned at anedge of the plastic half-shell top, wherein the at least one metal rivetis positioned at an edge of the automotive fluid pan bottom, and whereinthe metal rivet is a weld-on tubular rivet.
 17. The automotive fluidfiltration system of claim 16, further comprising a seal positionedbetween the automotive fluid pan bottom and the plastic half shell top.18. The integrated oil pan filter unit according to claim 1, wherein themetal rivet is attached by a weld.
 19. The automotive fluid filtrationsystem of claim 15, wherein the metal rivet is attached by a weld.